1.文章列表
- SpringCloud应用系列(1)config配置中心
- SpringCloud应用系列(2)eureka服务治理
- SpringCloud应用系列(3.1) ribbon服务调用
- SpringCloud应用系列(3.2) feign负载均衡
2.相关项目
- 注册中心：spring-cloud-eureka
- 服务提供者：spring-cloud-eureka-client
- 服务消费者: spring-cloud-hystrix
3. 服务端环境搭建
此次环境搭建主要是hystrix + ribbon来实现。
3.1 依赖导入
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
</dependency>
3.2 修改启动引导类
package com.roboslyq.springcloudhystrix;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.hystrix.EnableHystrix;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
@SpringBootApplication
@EnableDiscoveryClient
@EnableHystrix
public class SpringCloudHystrixApplication {
@Bean //定义REST客户端，RestTemplate实例
@LoadBalanced//开启负债均衡的能力
RestTemplate restTemplate() {
return new RestTemplate();
}
public static void main(String[] args) {
SpringApplication.run(SpringCloudHystrixApplication.class, args);
}
}
@EnableHystrix派生于@EnableCircuitBreaker,因此上面注解@EnableHystrix可以用注解@EnableCircuitBreaker来替代，最终效果一样。@Target(ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) @Documented @Inherited @EnableCircuitBreaker public @interface EnableHystrix { }
3.3 application.properties配置
#应用名称
spring.application.name=spring-cloud-hystrix
#端口号
server.port=8085
#注册中心的地址
eureka.client.serviceUrl.defaultZone=http://localhost:8082/eureka/
3.4 Hystrix包装Ribbon
package com.roboslyq.springcloudhystrix.service;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;
@Service
public class HystrixRibbonService {
@Autowired
private RestTemplate restTemplate;
//指定服务失败回调方法
@HystrixCommand(fallbackMethod = "helloError")
public String hello() {
String result = restTemplate.getForEntity("http://SPRING-CLOUD-EUREKA-CLIENT/hello", String.class).getBody();
System.out.println(result);
return result;
}
//失败回调方法
public String helloError(){
return "hello world is error!!!";
}
}
3.5 修改控制器类
package com.roboslyq.springcloudhystrix.controller;
import com.roboslyq.springcloudhystrix.service.HystrixRibbonService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class HystrixRibbonController {
@Autowired
HystrixRibbonService hystrixRibbonService;
@GetMapping("/hello")
public String hello(){
//调用服务
return hystrixRibbonService.hello();
}
}
4. 启动测试
4.1 检查注册中心
访问测试路径：http://localhost:8082/
Eureka注册中心如下;
| Application | AMIs | Availability Zones | Status |
|---|---|---|---|
| SPRING-CLOUD-EUREKA-CLIENT | n/a (1) | (1) | UP (1) - JK-LUOYONGQIAN.yx.yuexiu.com:spring-cloud-eureka-client:8083 |
| SPRING-CLOUD-HYSTRIX | n/a (1) | (1) | UP (1) - JK-LUOYONGQIAN.yx.yuexiu.com:spring-cloud-hystrix:8085 |
4.2 请求服务
### 4.2.1 正常情况
4.2.2 异常情况
停掉服务提供者spring-cloud-eureka-client 再请求路径http://localhost:8085/hello
由结果可知，已经进入熔断方法。